The present disclosure relates to a solid-state imaging device, a method of manufacturing the same, and an electronic device.
Electronic devices such as a digital video camera, a digital still camera, and the like include a solid-state imaging device. The solid-state imaging device includes for example a CMOS (Complementary Metal Oxide Semiconductor) image sensor and a CCD (Charge Coupled Device) image sensor.
The solid-state imaging device has a plurality of pixels arranged in an imaging plane. Each pixel includes a photoelectric conversion section. The photoelectric conversion section is for example a photodiode. The photoelectric conversion section receives light made incident via an external optical system on a light receiving surface, and subjects the light to photoelectric conversion. The photoelectric conversion section thereby generates a signal charge.
Of solid-state imaging devices, a CMOS image sensor has pixels configured to include not only a photoelectric conversion section but also a pixel transistor. The pixel transistor is configured to read out a signal charge generated in the photoelectric conversion section and output the signal charge to a signal line as an electric signal.
Solid-state imaging devices of a “frontside illumination type” and a “backside illumination type” are known. In the “frontside illumination type,” a photoelectric conversion section receives incident light made incident from the top surface side of a semiconductor substrate on which top surface side a pixel transistor, wiring, and the like are provided. Thus, in the case of the “frontside illumination type,” it may be difficult to improve sensitivity because the wiring and the like decrease an aperture ratio. On the other hand, in the case of the “backside illumination type,” sensitivity can be improved because a photoelectric conversion section receives incident light made incident from a bottom surface side on an opposite side from the top surface of a semiconductor substrate on which top surface a pixel transistor, wiring, and the like are provided (see Japanese Patent No. 3759435, for example).
A solid-state imaging device as described above has an effective pixel region and an optical black region provided in an imaging plane. The effective pixel region has effective pixels arranged therein, in which effective pixels a photoelectric conversion section receives incident light. The optical black region is provided on a part of the periphery of the effective pixel region, and has optical black (OB) pixels arranged therein, which OB pixels are provided with a light shielding layer for shielding a photoelectric conversion section from incident light. A black level reference signal is output from the OB pixels. The solid-state imaging device corrects signals output from the effective pixels with the signals output from the OB pixels as a reference so as to remove noise components such as a dark current and the like (see Japanese Patent Laid-Open No. 2005-347708, for example).